BirdAnalyst
Species · BCR 13 · BBS 2025 Release · 1966–2024

Common Grackle In Lower Great Lakes / St. Lawrence Plain

All regionsLower Great Lakes / St. Lawrence PlainGeneralists

Common Grackle in Lower Great Lakes / St. Lawrence Plain has fallen sharply: down 65% on the route-weighted index since 1968.

-65%Since 1968TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
86Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
58YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

long arc declinecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

Common Grackle has fallen sharply in Lower Great Lakes / St. Lawrence Plain: down 65% on the route-weighted index since 1968.

Common Grackle In Lower Great Lakes / St. Lawrence Plain Population Forecast

If the recent trend holds, Common Grackle in Lower Great Lakes / St. Lawrence Plain is projected to fall about 34% by 2029 — from 27 in 2024 to a central estimate of 18 (95% range 1.8–34). A 5-year backtest shows a typical error of ±8.3%, with 100% of held-out values landing inside the 95% band.

-34%Change by 2029TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
18Projected 2029 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
1.8–3495% range95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
±8.3%Backtest errorBacktest errorTypical error when we hold out the most recent years, forecast them, and compare to what actually happened. Lower means a more trustworthy projection.Full methodology →
If the recent trend holds, Common Grackle in Lower Great Lakes / St. Lawrence Plain is projected to fall about 34% by 2029 — from 27 in 2024 to a central estimate of 18 (95% range 1.8–34). A 5-year backtest shows a typical error of ±8.3%, with 100% of held-out values landing inside the 95% band.19662029
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →95% low95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →95% high95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
2025226.138
2026215.037
2027204.036
2028192.935
2029181.834

Routes In Lower Great Lakes / St. Lawrence Plain

Routes recording Common Grackle in Lower Great Lakes / St. Lawrence Plain.
Recent countThe raw number of individuals recorded on this route in its most recent survey year. A single-route tally, not a trend.Full methodology →
MacdougallNEW-YORK1912024
PeruOHIO1381978
Slippery RkPENNSYLVANIA961994
NaplesNEW-YORK762024
GarrettsvileOHIO761991
HebronOHIO702024
Cicero CtrNEW-YORK672024
RomulusNEW-YORK642000
HamburgNEW-YORK592024
Ballston LkNEW-YORK541995
North EastonNEW-YORK502024
HarmonsburgPENNSYLVANIA502023
LucerneOHIO492024
New SomersetOHIO481993
HiramOHIO482021
N VictoryNEW-YORK441972
Ferris CrnrsPENNSYLVANIA402024
ChurchvilleNEW-YORK392024
AkeleyPENNSYLVANIA381979
OgdensburgNEW-YORK372024
EspyvillePENNSYLVANIA362024
HopkintonNEW-YORK352021
RushvilleNEW-YORK322024
LattasburgOHIO312024
BranchportNEW-YORK302024

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.